Electric incandescent lamp



Sept. 21, 1937. K w|EGAND ET AL 2,093,878-

ELECTRIC INCANDESCENT LAMP Filed June 26, 1954 [Earl EN TUB. 5' KUR T I/I/FEGAND ALEXANDER Kama;

THEIR Ara-DANE Y Patented Sept. 21, 1937 UNITED STATES PATENT OFFICE ELECTRIC INCANDESCENT LAMP ration of New York Application June 26, 1934, Serial No. 732,542 In Germany July 13, 1933 3 Claims.

Our invention relates to electric incandescent lamps. More particularly our invention relates to incandescent lamps comprising a tubular bulb having a filament extending longitudinally thereof.

In incandescent lamps of the type referred to above the filament has heretofore been mounted on short support wires which in turn were mounted on a longitudinally extending stay rod or support wire which was disposed adjacent the wall of the tubular bulb. This type of support had the disadvantage that the support wires caused shadows to be formed on the wall of the said bulb.

An object of our invention is to provide a tubular lamp which will furnish illumination sub stantially free from shadows. According to our invention this object is attained by providing a filament which is strung in a zigzag or wavy path on support wires which extend alternately in opposite directions and are in turn mounted on a longitudinally extending stay rod or wire which is supported at a considerable distance from the wall of the bulb. The said longitudinally extending stay rod is preferably supported by transverse expanding spring members which engage the wall of the bulb at only three points and therefore do not create any substantial shadows. The said spring members are particularly advantageous in that they can easily be attached to 3 the longitudinal stay rod and they each provide a rugged three point means of support.

Further features and advantages of our invention will appear from the following detailed description thereof and from the drawing.

In the drawing, Fig, 1 is a side view of an in candescent lamp comprising our invention; Fig. 2 is a top view thereof; and Fig. 3 is a transverse sectional view thereof.

Referring to the drawing, the lamp comprises an elongated tubular bulb H), which may be evacuated or filled with an inert gas or gases, and bases ll, l2 at the ends thereof. A filament l3 consisting preferably of a helically coiled tungsten wire, extends through the bulb is, and is mounted on short support wires 14 which are in turn fastened to and insulated from a longitudinally extending stay rod or wire l5 by means of glass beads IS. The ends of the filament l3 are connected to lead wires I! by conductors !8. The stay rod I5 is fastened to the conductors 18 through insulating rods l9 so that only the filament carries the current. The support wires l4 extend alternately in opposite directions from the longitudinal stay rod [5 so that the filament I3 is strung thereon in a zigzag or waved path as shown in Fig. 2. The longitudinal stay rod I5 is supported at a considerable distance from the wall of the bulb III by Y-shaped expanding spring members 20 which are preferably disposed at uniform distances through the length of the bulb. The said spring members 20 are fastened to the stay rod l5 by glass beads 2| and make contact with the wall of the bulb at three points, thereby 5 providing a rigid support and at the same time leaving the said bulb substantially free from shadows.

The bulb [0 may be straight or curved in any desired manner. The shape of the spring mem- 1' bers 20 may also be modified without departing from the spirit of our invention. The bases may also be of a diiferent construction, and the bulb may be colored or frosted.

What we claim as new and desire to secure 13 by Letters Patent of the United States is:

1. An electric incandescent lamp comprising a tubular bulb, a stay rod extending longitudinally through said bulb and spaced from the wall thereof, a plurality of support wires carried by said stay rod and extending alternately in opposite directions, a filament extending longitudinally through said bulb in substantially a single plane parallel to the axis of said bulb, said filament being strung on said support wires in a zigzag path, 25 and transverse supports carrying said longitudinal stay rod and engaging the wall of said bulb.

2. An electric incandescent lamp comprising a tubular bulb, a stay rod extending longitudinally through said bulb and spaced from the wall 30 thereof, a plurality of support wires carried by said stay rod and extending alternately in opposite directions, a filament extending longitudinally through said bulb in substantially a single plane parallel to the axis of said bulb, said filament being strung on said support wires in a zigzag path, and substantially Y-shaped spring members carrying said longitudinal stay rod, the ends of said spring members engaging the wall of said bulb. 40

3. An electric lamp comprising a tubular bulb,

a stay rod extending longitudinally through said bulb and spaced from the wall thereof, a plurality of support wires carried by said stay rod and extending alternately in opposite directions, a filament extending longitudinally through said bulb in substantially a single plane parallel to the axis of the bulb, said filament being strung on said supports in a zigzag path, said stay rod extending parallel to the said plane of the filament and also being located in a plane passing along the axis of said bulb at right angles to the plane in which said filament is located, and transverse supports carrying said longitudinal stay rod and engaging the wall of said bulb. a

KURT W'IEGAND. ALEXANDER KOENIG. 

